#15 NoClassDefFoundErroron starting server

I have installed JBoss on Linux OS, JDK 1.3 and when I am trying to start the server by
executing ./run.sh I am getting this error -&quot;Couldn't find or load essential class &quot;java/lang/object&quot;
java.lang.NoClassFounderror java/lang/object&quot;

Please let me know what could be the problem as this is very urgent requirement.